Generally, injection molding machines incorporating an injection device and a mold clamping device are widely known as disclosed in JP-A-H04-79289 (patent document 1) and other documents. In this type of injection molding machine, typically, molding materials such as pellets are fed from the hopper of the injection molding machine into a heating cylinder, are plasticized and melted with a rotating screw in the heating cylinder and are measured, and then the molten resin measured through the forward movement of the screw is injected and filled into a cavity of the mold that is clamped by the mold clamping device. In this case, in order for the molding quality to be enhanced, the speed of the screw is controlled by feedback, and injection pressure (resin pressure) is also controlled by feedback. Thus, the amount of resin filled into the cavity of the mold is kept constant, and molding failures are avoided such as short shots due to insufficient filling and flash due to overfilling.
Incidentally, when attention is focused on molding materials, a variety of molding materials have become available, and special attention is given to recycle materials that are designed to be recycled. Recycle materials are obtained by mixing normal molding materials (virgin materials) with waste plastics, waste materials or the like (different types of materials), and thus, as a larger amount of different types of materials are mixed with virgin materials, recyclability is enhanced. However, since these different types of materials are likely to be solid materials such as grained materials, the evenness of a molding material as a whole is reduced. Therefore, when injection molding is conventionally controlled by feedback, it occurs that the property of the molding material (unevenness of the molding material) affects the molding quality more significantly than the control by the molding machine does. Hence, conventional injection molding machines encounter difficulties in molding recycle materials satisfactorily, and this problem becomes apparent as a larger amount of different types of materials are included.
An injection molding machine specialized for recycle materials is known by the disclosure of JP-A-2004-50427 (patent document 2). The injection molding machine for recycle materials disclosed in patent document 2 is composed of an injection-plunger-equipped injection device, a plasticization-screw-equipped plasticizing device that is disposed adjacent to the injection device and a distribution device that communicates with an injection cylinder and that is disposed in front of a plasticization cylinder. This injection molding machine is configured such that the distribution device and the plasticization cylinder are connected together via a foreign-material-removing device having a filter of a metal net inside it, and foreign materials in plasticized resin are removed by the filter and the resin can be fed to the injection device.